The latest update of Ghost has introduced a slightly different way of aggregating email open statistics. You can read more about the release here:
Release 5.94.0 · TryGhost/Ghost
🐛 Fixed “Unsaved changes” modal showing for some published posts with images - Kevin Ansfield
🐛 Fixed bookmark card hot linking icons and thumbnails (#20923) - Princi Vershwal
🐛 Fixed bookmark card…
TryGhost
This has broken the way the custom email integration of Magic Pages has worked. Emails were still sent out, but open events were not correctly shown in Ghost.
An attentive customer has noticed that and informed me today in the morning.
A fix has been rolled out to all Ghost sites on Magic Pages.